1. Field of the Invention
This invention relates to a retarding control apparatus operated by a manual changeover. More particually, the invention relates to a retarding control in which braking force due to a retarder is controlled depending upon the state of a manual shift or the steering angle of a wheel and slipping state.
2. Related Art
Relating to a first aspect of the present invention, a heavy vehicle often is equipped with an auxiliary brake such as an exhaust brake or hydraulic retarder in addition to a foot brake as braking means.
FIG. 1 illustrates an example of a conventional retarding control apparatus equipped with a hydraulic retarder. When a manually operated changeover swich 1 is turned on, an ECU 2 to which a changeover signal from the changeover switch 1 is applied outputs a current to a solenoid 3 to actuate a control valve 4 and introduce hydraulic pressure to a hydraulic retarder 5, whereby a braking force resulting from the retarder 5 is generated.